Add named constructor name checking

runtime/vm/parser.cc

Index: runtime/vm/parser.cc
===================================================================
--- runtime/vm/parser.cc	(revision 11907)
+++ runtime/vm/parser.cc	(working copy)
@@ -22,6 +22,8 @@
 
 namespace dart {
 
+DEFINE_FLAG(bool, constructor_name_check, false,
+            "Named constructors may not clash with other members");
 DEFINE_FLAG(bool, enable_asserts, false, "Enable assert statements.");
 DEFINE_FLAG(bool, enable_type_checks, false, "Enable type checks.");
 DEFINE_FLAG(bool, trace_parser, false, "Trace parser operations.");
@@ -480,6 +482,7 @@
     name_pos = 0;
     name = NULL;
     redirect_name = NULL;
+    constructor_name = NULL;
     params.Clear();
     kind = RawFunction::kRegularFunction;
   }
@@ -509,7 +512,11 @@
   const AbstractType* type;
   intptr_t name_pos;
   String* name;
-  String* redirect_name;  // For constructors: NULL or redirected constructor.
+  // For constructors: NULL or redirected constructor.
+  String* redirect_name;
+  // For constructors: NULL for unnamed constructor,
+  // identifier after classname for named constructors.
+  String* constructor_name;
   ParamList params;
   RawFunction::Kind kind;
 };
@@ -2399,6 +2406,14 @@
     ErrorMsg(method->name_pos,
              "field or method '%s' already defined", method->name->ToCString());
   }
+  if (FLAG_constructor_name_check && method->constructor_name != NULL) {
+    if (members->FunctionNameExists(*method->constructor_name, method->kind)) {
+      ErrorMsg(method->name_pos,
+               "Named constructor '%s' conflicts with method or field '%s'",
+               method->name->ToCString(),
+               method->constructor_name->ToCString());
+    }
+  }

[siva, 2012/09/06 16:52:10]

As discussed offline how do we report errors for the case of a field or function
appearing after the named constructor?

[hausner, 2012/09/06 18:02:13]

Correct. We really should have a simpler way to record the names in a scope. I
moved the check so it's now performed after the class is parsed. 

 
   // Mangle the name for getter and setter functions and check function
   // arity.
@@ -2865,8 +2880,8 @@
     if (CurrentToken() == Token::kPERIOD) {
       // Named constructor.
       ConsumeToken();
-      const String* name = ExpectIdentifier("identifier expected");
-      ctor_suffix = String::Concat(ctor_suffix, *name);
+      member.constructor_name = ExpectIdentifier("identifier expected");
+      ctor_suffix = String::Concat(ctor_suffix, *member.constructor_name);
     }
     *member.name = String::Concat(*member.name, ctor_suffix);
     // Ensure that names are symbols.